const main = (str) => {
	const strs = str.split('\n').slice(1).filter(v => v);
	const s = new Set();
	
	for (let i1 = 0; i1 < strs.length; i1++) {
		const s1 = strs[i1];
		for (let i2 = 0; i2 < strs.length; i2++) {
			const s2 = strs[i2];
			if (i1 !== i2) {
				s.add(s1 + s2);
			}
		}
	}
	
	return s.size + '';
};

console.log(main(require('fs').readFileSync('/dev/stdin', 'utf8')));